I have same experiences. If there is no BCCH-BSIC conflict, than check, if there is some HW problem. From cell trace compare UL and DL measurement – path balance. From statistic: there was a lot HO failure from two neighbors. There was difference between UL and DL 15 dB – wrong TMA. The next reason could be also wrong setting of parameters –ping pong HO. It is mostly on dual-band cels.